Anticorrosive composition

ABSTRACT

The present invention relates to the discovery that melanoidins, and higher molecular weight fractions of products containing melanoidins, provide significant corrosive inhibition, which render these melanoidins suitable for use as anticorrosive agents in corrosive environments. In addition to being highly anticorrosive, the melanoidins of the present invention are environmentally friendly and non-toxic, and can be found in animal food and in human foodstuffs.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. Provisional PatentApplication Ser. No. 61/059,981, filed Jun. 9, 2008.

FIELD OF THE INVENTION

This invention relates in general to corrosion caused by exposure to acorrosive environment and, more specifically, to the use of ananticorrosive agent that has a wide range of applicability in reducingcorrosion.

BACKGROUND OF THE INVENTION

Corrosion problems caused by exposure to and/or the use of chloride salthas been a longstanding problem in many applications and industries,including deicing and anti-icing for roadways and bridges (often causingrebar corrosion), oil well drilling operations, and other industrial andmarine applications carried out in corrosive environments. One commonindustrial application of chloride salts are their use in industrialbrines. A brine can be an aqueous solution of chloride salts alone, orin combination with sodium, potassium, calcium and magnesium cations.

One approach to address corrosion has been the addition of variousanticorrosive agents to the chloride salts or brines in order to reducethe corrosive effect. These various additives can be expensive. To alarge extent, these additives have been ineffective in controlling thecorrosivity of the brines. Similarly, the use of deicing formulations,which commonly include a chloride salt, inherently have a corrosiveeffect upon roadways, bridges (including rebar corrosion) and theenvironment. Various anticorrosive additives have been used with theseformulations with mixed success.

The prior art recognizes that the presence of carbohydrates such as cornsyrup and molasses, often used in deicing applications, reduces orinhibits corrosion at some level. However, when corrosion is an issuethat must be addressed, a separate corrosion inhibitor component isusually added to the carbohydrates. The main reason for this approach isthat excessive amounts of the carbohydrate would be required in order toobtain a significant anticorrosive effect due to the relatively smallamount of anticorrosive moiety contained in a given carbohydrate. Inthese cases, specific anticorrosive agents are selected and/orsynthesized to be effective in very small concentrations (very oftenless than 1%) so as not to affect the essential characteristics of thecarbohydrate, such as freezing point, viscosity and cost. In fact,excessive concentrations of carbohydrate to accomplish a significantreduction in corrosion could well render the carbohydrate unsuitable forits intended use (e.g., as an effective deicer).

It can be seen from above that there has been a longstanding need for asolution to these corrosion problems, including the effect on theenvironment.

BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to the discovery that melanoidins, andhigher molecular weight fractions of products containing melanoidins,provide significant corrosive inhibition, which render these melanoidinssuitable for use as anticorrosive agents in corrosive environments. Inaddition to being highly anticorrosive, the melanoidins of the presentinvention are environmentally friendly and non-toxic, and can be foundin animal food and in human foodstuffs. There are a number ofapplications and industries where corrosion is a problem that theseadditives can be used (e.g., additives to industrial brines, deicingformulations for roadways and bridges, oil well drilling, and in otherindustrial and marine applications where corrosion is a problem).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a GPC profile for sucrose.

FIG. 2 illustrates a GPC profile for a component having a molecularweight of 12,400.

FIG. 3 illustrates a GPC profile for 79.5 Brix Molasses.

FIG. 4 illustrates a GPC profile for Fraction A obtained from thealcohol precipitation of the molasses.

FIG. 5 illustrates a GPC profile for the higher molecular weightfraction (retentate) obtained from the dialysis of Fraction A.

FIG. 6 illustrates a GPC profile for the lower molecular weight fraction(permeate) obtained from the dialysis of Fraction A.

FIG. 7 illustrates a GPC profile for the higher molecular weightfraction (retentate) obtained from the ultrafiltration of the molasses.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to the discovery that melanoidins, andhigher molecular weight fractions of products containing melanoidins,provide significant corrosive inhibition, which render these melanoidinssuitable for use as anticorrosive agents in corrosive environments.

Melanoidins are brown-colored polymers formed by the interaction ofamino acids and carbohydrates (e.g., mono-, di-, and oligosaccharides).Melanoidins are formed by a reaction between carbohydrates/saccharidesand amino acids during aqueous processing at elevated temperatures(e.g., 70 to 120° C.). This is known as the Maillard Reaction which is acomplex reaction with a network of consecutive and parallel chemicalreactions.

Although the molecular weights of melanoidins can vary from about 400 tomore than 100,000 depending upon reaction conditions (e.g., temperature,time, pH, water content), the molecular weight of the melanoidinssuitable for use in the present invention is above about 10,000, with apreferred range being about 12,400 and higher (i.e., higher molecularweight melanoidins).

Melanoidins contain groups (e.g., amino, carboxyl) which can chelateferrous ions. In the corrosion cell, ferrous ions are produced at thesteel anode. Inhibition of the corrosion process at the anode occurswhen chelation/complexation of the ferrous ions occur. It has been shownthat the type of saccharide is a significant factor in the chelationreaction. For example, glucose is more efficient than the disaccharidelactose in iron binding ability. It has also been shown thatglucose/glutamic acid readily complexes with several cations e.g. Mg²⁺,Cu²⁺, Ca²⁺ and Zn²⁺. Therefore anodic inhibition will occur.

The cathode in the corrosion cell requires the presence of oxygen forcorrosion to occur. Removing oxygen causes cathodic inhibition.Melanoidins from the Maillard Reaction have been shown to haveanti-oxidative properties. Researchers have examined a glucose/glycinemodel and found anti-oxidation effects. Others have used theglucose/glycine model and found that the high molecular weight fraction,with a molecular weight greater than 12,400 was significantly moreeffective than other fractions. Still others have examined MaillardReaction products from lactose/lysine model systems and concluded thathigh molecular weight fractions were more colored and had the highestanti-oxidative activity. Therefore cathodic inhibition will occur.

Molasses derived from sugar cane was selected as the exemplary sourcefor obtaining the higher molecular weight melanoidins of the descriptionof the present invention. Melanoidins are present in molasses, which isa product of the manufacture and/or refining of sucrose from mainlysugar cane or sugar beets, although molasses can be obtained from theprocessing of citrus fruit, starch (from corn or grain sorghum) which ishydrolyzed by enzymes and/or acid, also from hemicellulose extract whichis a product of the manufacture of pressed wood. However, the scope ofthe present invention is not limited to a particular source ofmelanoidins, which may be derived from various agricultural sources(e.g., corn, wheat, barley, rice, sugar beets. and sugar cane, whichafter processing, yield other products), corn steep liquor (CSL),brewers condensed solubles (BCS), and distillers condensed solubles(DCS). In addition, other products having similar molecular weight (GPC)profiles to these known examples with respect to higher molecular weightcomponents and fractions would also provide melanoidins suitable forcorrosion inhibition.

It is known that a mix (e.g., 80/20) of salt brine and molasses (e.g.,79.5 Brix Molasses) provides significantly more corrosion inhibition ascompared to the corrosion caused by the salt brine alone. In order toidentify the components in the molasses that contribute to theanticorrosive effect of the product, chromatographic separation (e.g.,column chromatography, gel permeation chromatography) can be used toseparate the components of a mixture by size, with the results shown ona chromatogram profile.

For example, in some of the experiments described herein, chromatogramprofiles were obtained on various diluted samples using gel permeationchromatography (GPC) under the following chromatography conditions:Column (Bio-S-3000), Mobile Phase (Sodium Azide 0.05%), Detector(Refractive Index), Flow Rate (1.0 mL/min), Injection Volume (10.0 μL),and Run Time (20 minutes).

FIGS. 1 through 7 show GPC profiles for various samples. Each profileshows peaks for the molecular weights of components present in thesample. Peaks do not necessarily represent a single compound, but,particularly at higher molecular weight ranges, may be comprised ofmultiple components or polymers having heterogeneous composition. Eachprofile also provides the elapsed time before a particular molecularweight component was released from the column (retention time (RT)). Asgeneral rule, the higher the molecular weight of the component, theshorter the retention time. Likewise, the lower the molecular weight ofthe component, the longer the retention time. Each profile also providesthe height and area of the peak representing a particular molecularweight component, which allows for the determination of the weightpercent of that particular molecular weight in the sample.

For example, FIG. 1 illustrates a GPC profile for sucrose (MW=342)having a retention time under those particular test conditions of 15.371minutes. Similarly, FIG. 2 illustrates a GPC profile for a componenthaving a molecular weight of 12,400 having a retention time under thosesame test conditions of 12.993 minutes. Accordingly, based on thosestandards and under those same test conditions, for components withmolecular weights less than 342, one would expect retention times longerthan 15.371 minutes. Similarly, for components with molecular weightsgreater than 12,400, one would expect retention times shorter than12.993 minutes.

FIG. 3 illustrates a GPC profile for 79.5 Brix Molasses, which shows aretention time of 15.360 minutes for the most significant peak (i.e.,the largest concentration has a molecular weight that corresponds to aretention time of 15.360 minutes). Comparing this GPC profile for themolasses (FIG. 3) to the GPC profile for sucrose (MW=342) (FIG. 1) andthe GPC profile for a molecular weight standard of 12,400 (FIG. 2), onecan see that there is a significant concentration of sucrose in themolasses and other lower molecular weight components in the molasses(i.e., that would have retention times near 15.371 minutes for sucrose).There is also a very low concentration of higher molecular weightcomponents (i.e., that would have retention times near or less than12.993 minutes for a MW=12,400).

Turning to the experiments used to identify the components in themolasses that contribute to the anticorrosive effect of the product, inone experiment, 79.5 Brix Molasses (200 g/150 mL) was diluted (1:1) withdistilled water (200 g/200 mL) and then separated into five fractions(A-E) by adding increasing amounts of denatured alcohol (85% ethanol/15%methanol) employing an alcohol precipitation method by sequentialaddition. Alcohol precipitation is one method of selective precipitationwidely used for isolating higher molecular weight fractions fromheterogeneous mixtures. In alcholol precipitation, denatured alcohol isused as the non-solvent in a step-wise manner, filtering off theprecipitate between each addition.

Fraction A was a precipitate with the least amount of the alcoholmixture and contained the highest molecular weight components, whilefraction E had the greatest amount of the alcohol mixture and was thelowest molecular weight fraction of the molasses. These precipitatescould be filtered and dried.

FIG. 4 illustrates a GPC profile for Fraction A with eight peaks,showing the inclusion of higher molecular weight components withretention times near or shorter than the retention time for MW=12,400(RT=12.993 minutes), but still having a significant amount of lowermolecular weight components with retention times near or longer than theretention time for sucrose (MW=342) (RT=15.371 minutes).

A 100 ml sample of each fraction (A-E) was then mixed with 400 ml of 30%NaCl to yield an 80/20 mix for corrosion rate testing according to theNACE Standard TM-01-69 Method as modified by the Pacific NorthwestSnowfighters (PNS).

Corrosion rate testing showed that certain fractions include corrosioninhibiting components, with fractions A (55.5% reduction), B (29.4%reduction), and E (63.2% reduction) all reducing the corrosiveness ofthe magnesium chloride when used alone.

Organic acid analysis of the molasses and these fractions demonstratedthat trans-aconitic acid, which comes from sugar cane, is present in themolasses (1.63%), and more specifically, Fraction A (0.88%) and fractionB (0.23%), but is absent from fraction E. Aconitic acid is a compoundfound in sugar processing and is the main organic acid in sugar juiceand in raw sugar. Aconitic acid is bound or associated withpolysaccharides with a molecular weight of 300,000.

Protein analysis of the molasses and these fractions demonstrated thatprotein is present in molasses (5.2%), and more specifically, Fraction A(1.9%) and fraction E (1.6%).

Amino acid analysis of the molasses and these fractions demonstratedthat amino acids are present in the molasses (0.37%), and morespecifically, in trace concentrations in Fraction A and fraction E, withaspartic acid having the most significant concentration (0.25%).

Carbohydrate analysis of these fractions demonstrated that theconcentration of carbohydrates present (after dilution) in fraction E(5.25%) are sufficient to account for the bulk of the corrosioninhibition shown by that fraction, but the low concentrations ofcarbohydrates present in fractions A (0.78%) and B (0.40%) are notsufficient to account for corrosion inhibition shown by those fractions.

Corrosion rate testing on the molasses and selected carbohydratespresent in the molasses demonstrated that the corrosion inhibition ofthe molasses is greater than that of its constituent carbohydratesalone. Furthermore, corrosion rate testing demonstrated that highermolecular weight (HMW) Fraction A, which contains 25% of the totalsolids in the molasses, exhibits similar corrosion inhibition to lowermolecular weight (LMW) fraction E, which contains 60% of the totalsolids in the molasses.

Given that data, it was shown that, on a weight basis, the highermolecular weight components in Fraction A have approximately twice thecorrosion inhibition activity of the lower molecular weightcarbohydrates in fraction E. This suggested the presence of highermolecular weight components in Fraction A other than carbohydrates arelargely responsible for the corrosion inhibition demonstrated by thatfraction. These higher molecular weight components are melanoidins.

These various analyses also indicated that approximately 23% of thetotal solids in the molasses are not organic acids, proteins, aminoacids, or carbohydrates, with a significant amount of those unidentifiedsolids (3.5%) present in fractions A and E, which show corrosioninhibition.

To further identify the higher molecular weight components in themolasses and Fraction A (prepared using alcohol precipitation) that arelargely responsible for corrosion inhibition, various techniques can beused, including selective precipitation, dialysis, ultrafiltration, or acombination of those techniques.

In another experiment, the 79.5 Brix molasses was subjected to dialysisat room temperature using a regenerated thin semi-permeable cellulose(RC) Spectrum Laboratories membrane with a defined molecular weightcut-off of 12,400. The membrane allows the components having molecularweights below the cut-off to pass through or permeate the membrane(“permeate”), leaving behind the components having molecular weightsabove the cut-off (and lower molecular weight components closelyassociated with them) that are stopped or retained by the membrane(“retentate”).

In the experiment, 3 g of the molasses was dissolved in 30 mL ofdistilled water contained in the cellulose membrane, which was thenplaced in a 2 L beaker containing 500 mL of distilled water. A magneticstirrer agitated the contents of the beaker. After at least 24 hours ofdialysis, the membrane package containing the brown higher molecularweight fraction (retentate) was removed from the yellow lower molecularweight fraction (permeate). The brown retentate was then dissolved in500 mL of distilled water.

The brown higher molecular weight fraction (retentate) contained thehigher molecular weight components with molecular weights greater thanthe cellulose membrane cut-off (12,400) as well as lower molecularweight components that are closely associated with the higher molecularweight components stopped or retained by the membrane. The brown colorand molecular weight data indicates the presence of melanoidins in thehigher molecular weight fraction (retentate).

The yellow lower molecular weight fraction (permeate) contained thelower molecular weight components with molecular weights less than themembrane cut-off (12,400) that passed through or permeated the membrane.The yellow color and molecular weight data tends to indicate the absenceor limited presence of melanoidins in the lower molecular weightfraction (permeate).

After the dialysis of the molasses, both the resulting higher molecularweight fraction (retentate) and the lower molecular weight fraction(permeate) contained the relative amounts of components that would bepresent in a solution of 0.6% molasses (3 g molasses/500 mL distilledwater).

Separate corrosion rate testing was performed on solutions of sodiumchloride (3%) combined with molasses, the higher molecular weightfraction (retentate), and the lower molecular weight fraction (permeate)using a method based on the PNS test, modified to increase the speedrequired to perform the test.

The results of the corrosion rate testing are shown in Table 1.

TABLE 1 Steel Corrosion Inhibitor Metal Corrosion Chloride Solution(Weight % & mg/mL) Loss (mg) Reduction (%) 3% NaCl None 49.4 None (3,000mg/100 mL) 3% NaCl 0.6% Molasses 20.40 62.3 (3,000 mg/100 mL) (424.2mg/100 mL) 3% NaCl 0.6% HMW retentate 13.04 75.9 (3,000 mg/100 mL) (63.0mg/100 mL) 3% NaCl 0.6% LMW permeate 23.92 55.8 (3,000 mg/100 mL) (notrecorded)

The percent reduction in corrosion for a particular solution iscalculated by taking the difference between steel metal loss for thatsolution and the steel metal loss for the chloride salt solution anddividing that difference by the steel metal loss for the chloride saltsolution, and multiplying that ratio by 100.

${\% \mspace{14mu} {CR}} = {\frac{w_{1} - w_{2}}{w_{1}} \times 100}$

where

w₁=weight loss of uninhibited chloride solution

w₂=weight loss of inhibited chloride solution

These results demonstrate that the higher molecular weight fraction(retentate) is a far more potent corrosion inhibitor than the molassesor the lower molecular weight fraction (permeate), despite the fact thatthe solids content of the retentate (63.0 mg/100 mL) is significantlyless than the solids content of the molasses (424.2mg/100 mL) and thepermeate (not recorded but approximately 360 mg/100 mL). For example,even though the higher molecular weight fraction (retentate) has almostseven times less solids content than the molasses (i.e., only representsapproximately 15% of the dry weight molasses or 10% of the liquidmolasses), it provides a much greater reduction in corrosion. Themelanoidins present in the higher molecular weight fraction (retentate)inhibit corrosion by both anodic and cathodic inhibition.

Separate corrosion rate testing was performed on solutions of sodiumchloride (3%), magnesium chloride (3%), and calcium chloride (3%)combined with the higher molecular weight fraction (retentate) using themodified PNS test. Triplicate 10 mL samples were evaporated to drynessin an oven for one hour at 105° C., cooled in desiccators for thirtyminutes and weighed. The cycle of drying, cooling, and desiccating, andweighing was continued until a constant weight (in mg/100 mL) wasobtained.

The results of the corrosion rate testing are shown in Table 2.

TABLE 2 Steel Corrosion Inhibitor Metal Corrosion Chloride Solution(Weight % & mg/mL) Loss (mg) Reduction (%) 3% NaCl None 49.4 None (3,000mg/100 mL) 3% NaCl 0.3% HMW retentate 20.0 59.5 (3,000 mg/100 mL) (25.6mg/100 mL) 3% NaCl 0.6% HMW retentate 17.6 64.4 (3,000 mg/100 mL) (57.8mg/100 mL) 3% NaCl 1.0% HMW retentate 12.0 75.7 (3,000 mg/100 mL) (105.9mg/100 mL) 3% MgCl₂ None 17.27 None (3,000 mg/100 mL) 3% MgCl₂ 0.6% HMWretentate 7.06 59.1 (3,000 mg/100 mL) (65 mg/100 mL) 3% CaCl₂ None 38.10None (3,000 mg/100 mL) 3% CaCl₂ 0.6% HMW retentate 6.54 82.8 (3,000mg/100 mL) (62.2 mg/100 mL)

These results demonstrate that as the concentration of the highermolecular weight fraction (retentate) is increased, the corrosiveinhibition also increases. Similar results when combined with otherchloride salts (e.g., potassium chloride) would be expected. Themelanoidins present in the higher molecular weight fraction (retentate)inhibit corrosion by both anodic and cathodic inhibition.

In another experiment, Fraction A of the 79.5 Brix Molasses was obtainedusing the alcohol precipitation method described above. Recall that FIG.4 illustrates a GPC profile for Fraction A, showing the inclusion ofhigher molecular weight components with retention times near or shorterthan the retention time for MW=12,400 (RT=12.993 minutes), but stillhaving a significant amount of lower molecular weight components withretention times near or longer than the retention time for sucrose(MW=342) (RT=15.371 minutes). Fraction A was then subjected to the samedialysis process described above for the molasses using a cellulosemembrane with a defined molecular weight cut-off of 12,400.

After dialysis, the higher molecular weight fraction (retentate) ofFraction A had a brown color (similar to but less intense than the colorof Fraction A) and contained the higher molecular weight components withmolecular weights greater than the cellulose membrane cut-off (12,400)as well as lower molecular weight components that are closely associatedwith the higher molecular weight components stopped or retained by themembrane. FIG. 5 illustrates a GPC profile for the higher molecularweight fraction (retentate) of Fraction A, indicating a major unimodalpeak at a retention time of approximately 12 minutes, which is near andshorter than the retention time for MW=12,400 (RT=12.993 minutes). Thisillustrates the increased concentration of higher molecular weightcomponents in the higher molecular weight fraction (retentate) ofFraction A (FIG. 5) as compared to Fraction A (FIG. 4). The brown colorand molecular weight data indicates the presence of melanoidins in thehigher molecular weight fraction (retentate) of Fraction A.

The lower molecular weight fraction (permeate) of Fraction A had abright yellow color and contained the lower molecular weight componentswith molecular weights less than the membrane cut-off (12,400) thatpassed through or permeated the membrane. FIG. 6 illustrates a GPCprofile for the lower molecular weight fraction (permeate) of FractionA, showing five peaks, all with retention times longer than theretention time for MW=12,400 (RT=12.993 minutes). This illustrates thetheoretical absence of all higher molecular weight components in thelower molecular weight fraction (permeate) of Fraction A that werestopped or retained by the cellulose membrane. The yellow color andmolecular weight data tends to indicate the absence or limited presenceof melanoidins in the lower molecular weight fraction (permeate) ofFraction A.

Molasses Fraction A was subjected to hydrolysis using 2M trifluoroaceticacid heated at 120° C. for 2 hours. No increase in carbohydrate peakswas observed. The acid caused a precipitate to form related to the HMWmaterial. The addition of sodium hydroxide to neutralize the acid causedthe HMW material to dissolve and again be detected by GPC.

In another experiment, ultrafiltration was used to identify the highermolecular weight components in the 79.5 Brix Molasses that are largelyresponsible for corrosion inhibition. Ultrafiltration is apressure-driven process where a fluid stream is pumped at low pressureand high flow rate across the surface of thin semi-permeable polymericmembranes with a defined molecular weight cutoff. As with dialysispreviously described, ultrafiltration uses a membrane having a definedmolecular weight cut-off that allows components having molecular weightsbelow the cut-off to pass through or permeate the membrane (“permeate”),leaving behind the components having molecular weights above the cut-off(and lower molecular weight components closely associated with them)that are stopped or retained by the membrane (“retentate”). Theultrafiltration equipment used for the experiment was Quix StandUltraFiltration System (Amersham Biosciences, GE Healthcare) with aHollow Fiber Cartridge UFP-10-E-3 MA with a nominal molecular weightcut-off of 10,000 and surface area of 110 cm².

In the experiment, 10 g of molasses was added to 800 mL of distilledwater, mixed, and added to the feed reservoir of the ultrafiltrationsystem to obtain a higher molecular weight fraction (retentate) withcomponents having molecular weights above 10,000 and a lower molecularweight fraction (permeate) with components having molecular weightsbelow 10,000. GPC profiles were then obtained using a High PressureLiquid Chromatograph (HPLC) with a Waters 410 Differential Refractometerunder the same chromatography conditions as previously described.

The reference retention times determined for comparison to some of thelater-obtained test results are shown in Table 3.

TABLE 3 Retention Time Molecular Weight (minutes) 342 (Sucrose) 11.38 1,400 10.61  6,900 9.49 12,400 8.93 20,100 8.41

FIG. 7 illustrates a GPC profile for the higher molecular weightfraction (retentate) obtained from the ultrafiltration of the molasses.The GPC profile for the higher molecular weight fraction (retentate)shows a total of ten peaks.

The retention times, weight percents, and molecular weights for each ofthe peaks are shown in Table 4.

TABLE 4 % Area Under Time Minutes Curve Molecular Weight 5.753 2.15Greater than 100,000 7.634 0.89 40,000 8.536 1.68 18,500 8.789 1.3414,000 9.150 5.36 10,000 9.594 7.28 7000 10.296 20.69 2700 10.866 0.47990 11.412 54.27 342 11.768 5.89 180

Based on the retention time for the standard MW=12,400 (RT=8.93), theGPC profile shows that higher molecular weight components with molecularweights greater than 12,400 make up approximately 6% by weight of thehigher molecular weight fraction (retentate), while higher molecularweight components with molecular weights greater than or equal to 10,000make up approximately 10% of the retentate. Based on the results of theearlier experiments demonstrating that the higher molecular weightfractions (retentate) exhibited superior corrosion inhibition overmolasses, additional corrosion rate testing was performed using theretentate from the ultrafiltration process to confirm these earlierresults.

The results of the corrosion rate testing are shown in Table 5.

TABLE 5 Steel Corrosion Metal Corrosion Corrosion Inhibitor InhibitorLoss Reduction Chloride Solution (mg/100 mL) (ppm) (mg) (%) 3% NaCl NoneNone 74.81 None (3,000 mg/100 mL) 3% NaCl Molasses 8,870 43.65 41.65(3,000 mg/100 mL) (904.5 mg/100 mL) 3% NaCl Molasses 2,150 46.15 38.31(3,000 mg/100 mL) (219.2 mg/100 mL) 3% NaCl HMW retentate 2,440 26.9064.04 (3,000 mg/100 mL) (248.8 mg/100 mL) 3% MgCl₂ HMW retentate 58539.36 47.39 (3,000 mg/100 mL) (59.7 mg/100 mL)

These results once again demonstrate the superior corrosive inhibitionof the higher molecular weight fraction (retentate) as compared to themolasses. For example, although the concentration of molasses (904.5mg/100 mL) on a weight basis is approximately fifteen times greater thanthe concentration of the higher molecular weight fraction (retentate)(59.7 mg/100 mL) in one example, the retentate resulted in approximately6% greater corrosion reduction (a relative improvement of approximately14%).

Based on that data, on a weight basis, the higher molecular weightfraction (retentate) is approximately 17 times more efficient as acorrosion inhibitor than molasses (i.e., 14% improvement on top of aweight difference of 15 times). The previously described experimentshave shown that it is the higher molecular weight components in theretentate of the molasses (i.e., those components with molecular weightsgreater than 10,000 or 12,400) that provide the greatest and mostunexpected corrosion inhibition. Those components only constitute 6% to10% of the weight of the retentate. Given this data, those highermolecular weight components are approximately 170 to 280 times moreefficient as a corrosion inhibitor than molasses on a weight basis. Themelanoidins present in the higher molecular weight fraction (retentate)inhibit corrosion by both anodic and cathodic inhibition.

There are a number of applications and industries where corrosion is aproblem that additives including melanoidins (or higher molecular weightfractions of melanoidin-containing products) can be used (e.g.,additives to industrial brines, deicing formulations for roadways andbridges, oil well drilling, and in other industrial and marineapplications where corrosion is a problem). Any suitable concentrationof the higher molecular weight fraction of the melanoidin-containingproduct that effectively reduces corrosion in a chloride salt, brine, ora deicing formulation may be used. A typical concentration can vary fromabout 0.03 to 10.0% by weight. For example, one embodiment of a deicingformulation using the melanoidins of the present invention is as anadditive to a known deicing and anti-icing formulation:

Weight % Low Molecular Weight Carbohydrate 3 to 60 Inorganic FreezingPoint Depressant 5 to 35 HMW Fraction of Melanoidin- 0.03 to 10.0 Containing Product Thickener 0.15 to 10 (optional)

The basic composition of the known deicing formulation consists of atleast the first two of the following three components in aqueoussolution depending upon ambient weather conditions, terrain, nature andamount of freezing/snow precipitation, and environmental concerns:

(1) Inorganic freezing point depressants preferably in the form ofchloride salts which include magnesium chloride, calcium chloride andsodium chloride. Metal acetates e.g. calcium magnesium acetate, may alsobe used.

(2) Low molecular weight carbohydrates in the 180 to 1,500 range(180-1,000 preferred) wherein the carbohydrate is at least one selectedfrom the group consisting of glucose, fructose and higher saccharidesbased on glucose and/or fructose and mixtures thereof. Thesecarbohydrates can be obtained from a wide range of agricultural basedproducts such as those derived from corn, wheat, barley, oats, sugarcane, sugar beets etc and products such as corn syrup and molasses.

(3) Thickeners are used in certain applications as the third keycomponent to increase the viscosity of the composition so that theliquid remains in contact with the road surface or with the solidparticles in piles of rocksalt/sand, or rocksalt/aggregates, or saltalone, or sand or aggregate. Thickeners are mainly cellulose derivativesor high molecular weight carbohydrates. Typical molecular weights forcellulose derivatives are for methyl and hydroxy propyl methylcelluloses from about 60,000 to 120,000 and for hydroxy ethyl cellulosesfrom about 750,000 to 1,000,000. Carbohydrate molecular weights rangefrom about 10,000 to 50,000.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to make and use the invention. The patentable scope of the inventionis defined by the claims, and may include other examples that occur tothose skilled in the art. Such other examples are intended to be withinthe scope of the claims if they have structural elements that do notdiffer from the literal language of the claims, or if they includeequivalent structural elements with insubstantial differences from theliteral language of the claims.

1. An anticorrosive composition comprising: a molecular weight fractionof a melanoidin-containing product, wherein said molecular weightfraction comprises substantially all of the available melanoidin specieshaving a molecular weight greater than or equal to 10,000 in saidproduct.
 2. The anticorrosive composition of claim 1, wherein saidmolecular weight fraction comprises substantially all of the availablemelanoidin species having a molecular weight greater than or equal to12,400 in said product.
 3. The anticorrosive composition of claim 1,wherein said melanoidin-containing product is selected from the groupconsisting of molasses, corn steep liquor, brewers condensed solubles,and distillers condensed solubles.
 4. The anticorrosive composition ofclaim 1, wherein the source of said melanoidin containing agricultureproduct or by-product is at least one selected from the group consistingof sugar cane, sugar beets, corn, wheat, barley, and rice.
 5. Theanticorrosive composition of claim 1, further comprising a brine.
 6. Theanticorrosive composition of claim 1, further comprising a chloridesalt.
 7. The anticorrosive composition of claim 6, wherein said chloridesalt is at least one selected from the group consisting of sodiumchloride, magnesium chloride, calcium chloride, and potassium chloride.8. The anticorrosive composition of claim 6, further comprising a lowmolecular weight carbohydrate having a molecular weight in the range ofabout 180 to 1500, wherein said carbohydrate is at least one selectedfrom the group consisting of glucose, fructose and higher saccharidesbased on glucose and/or fructose and mixtures thereof.
 9. Theanticorrosive composition of claim 8, further comprising a thickenerselected from the group consisting of high molecular weight cellulosederivatives and carbohydrates in the range of about 60,000 to 1,000,000for cellulose derivatives and 10,000 to 50,000 for carbohydrates.